47 



Spikes rarely solitary ; spikelets 2-nate, 2-fld., 

 a\vne<l. 33. Ischce'imtm. 



Spikes solitary, spikelets 1-fld., gl. I pectinate. 



34. EremocJdoa. 



** M.'irgins of gl. I of sessile spikelcts not inflexed. 

 Spikes solitary ; spikelets 2-nate, 1 -2-fld., 2-awned. 



35. Pogonatlierum, 

 Spikes digitate ; spikelets 1-fld., 



3G. Artkraxon. 



Subtribe V. Apludece. Spikelets 3 on an inarticulate 

 rachis. 37. Apluda. 



Subtribe VI. Rottboelliece. Spikelets homo- or hetero-gamous, 

 1-2-fld., solitary, or 2- rarely 3-nate on the internodes 

 of an articulate spike or raceme, not awned., gl. I 

 not keeled, aduate to or sunk in a depression formed 

 by the iiiternode and pedicel of the upper spikelets; 

 gls. of sessile spikelet 4. 



Spikelets 2-nate, gl. I flat. 38. Eoitboellia. 



Spikelets 2-nate, gl. I globose. 39. Manisuris. 



Spikelets solitary, gl. I convex. 40. Opliiurus. 



Subtribe VII. Euandropogonece. Spikelets heterogamoua 



1-fld., 2- rarely 3-nate on the whorled articulate 



branches of simple or compound racemes or panicles, 



gls 4, I not keeled, IV usually awned. 



Sessile spikelets of all the pairs alike in sex and 

 form throughout the spikes. 



Joints of rhachis and pedicels of upper spikelets 

 linear, compressed, with usually a central trans- 

 lucent channel and thickened margins. 



41. Andropogon. 



Joints of rachis very few, filiform, opaque ; 

 lodiceles cilia te; grain dorsally compressed. 



42. Sorghum. 



